What bioremediation techniques are currently used at hazardous waste sites?
1. Surface and subsurface bioremediation If the contamination is in the top part of the soil (less than 12 inches) it can be treated by tilling the soil to provide aeration and by adding nutrients and water for bacterial growth. Sometimes oxygen must be delivered to the contaminated area for the respiration process because oxygen is not very soluble and easily depleted. This is done by withdrawing the ground water, adding an oxygen source such as (air, pure oxygen, hydrogen peroxide, or ozone) and re-injecting the water using injection wells or trenches. 2. Above ground bioremediation Slurry-phase treatment is a process that combines contaminated soil with water to create a slurry, which is broken down in a bioreactor. If necessary, nutrients and oxygen can be added. The soil and water are separated after treatment. Solid-phase treatment is another treatment where contaminated soils are placed in a treatment bed where nutrients, moisture and oxygen are added for decomposition to take p
